The invention relates to an alarm device for respirators with a connection for the pressure gas supply and a signal whistle arranged in a receiving part, and with a device for changing the acoustic signal.
Such alarm devices are known from German AS 24 56 189. There the alteration of the acoustic signal is achieved in that the gas supply is periodically opened and closed by way of a valve. so that a short succession of whistle tones warns the wearer of the respirator when the gas supply pressure has fallen below a certain level. The frequency of the whistle tones can be influenced by a throttle point with variable flow cross-section, which is disposed in the gas supply line associated with the valve.
The frequency, once adjusted with the aid of the throttle, is not adjusted during the entire time that the respirator is worn. Suitable sound-generating signal whistles are for example lip or reed whistles.
If several respirator wearers must work jointly at a site, and if on one of them the known alarm signal is sounded, indicating a low pressure condition, the wearers cannot distinguish whether their alarm has sounded on their respirator or the alarm of another wearer has sounded. Checking his own gas supply after occurrence of an alarm signal, for example by visual inspection of the supply pressure gauge, is not possible for the wearer working with a gas mask and under difficult viewing conditions which are often encountered. The wearer must often work in smoke or darkness or lenses of his mask may be fogged on the outside.